White light emitting material, preparation method thereof, and application thereof

Abstract

A white light emitting material having a chemical structural formula represented by formula (I), a preparation method thereof and application thereof. The preparation method comprises subjecting tris(4-iodophenyl)amine and 4-methoxyphenylacetylene or tris(4-iodophenyl)amine and methyl 4-ethynylbenzoate to a coupling reaction under protection of a protective gas and catalysis of a Pd/Cu mixed catalyst, to obtain the white light emitting material. A novel temperature-sensitive light emitting material is synthesized through a one-step method. The material is applied to the field of diode luminescence based on the temperature-sensitive characteristic. White light luminescence can be finally realized only by reasonably controlling the temperature and duration time during heating a substrate. Compared with the existing art, the method greatly saves raw material costs and manufacturing process costs, and provides a novel idea and strategy for use of a white organic light emitting diode.

Claims

1. A white light emitting material having a chemical structural formula represented by formula (I): ##STR00004## wherein —R is selected from —OCH.sub.3 or —COOCH.sub.3.

2. A preparation method of the white light emitting material of claim 1, comprising: subjecting tris(4-iodophenyl)amine and 4-methoxyphenylacetylene or tris(4-iodophenyl)amine and methyl 4-ethynylbenzoate to a coupling reaction under protection of a protective gas and catalysis of a Pd/Cu mixed catalyst, to obtain the white light emitting material.

3. The preparation method of the white light emitting material of claim 2, wherein the protective gas is nitrogen.

4. The preparation method of the white light emitting material of claim 2, wherein the Pd/Cu mixed catalyst is a catalyst consisting of tetrakis(triphenylphosphine)palladium and cuprous iodide; optionally, a molar ratio of tetrakis(triphenylphosphine)palladium to cuprous iodide is 1:(2 to 10).

5. The preparation method of the white light emitting material of claim 2, wherein the coupling reaction is carried out in a mixed solvent of tetrahydrofuran and triethylamine; optionally, a volume ratio of tetrahydrofuran to triethylamine is (2 to 6):1.

6. The preparation method of the white light emitting material of claim 2, wherein the coupling reaction is carried out at 70° C. to 90° C.; optionally, a product of the coupling reaction is purified by column chromatography.

7. A white organic light emitting diode, comprising a substrate, an anode layer, a hole injection layer, a white light emitting layer, an electron transport layer, an electron injection layer and a cathode layer, which are sequentially stacked, wherein a material for the white light emitting layer is the white light emitting material of claim 1.

8. The white organic light emitting diode of claim 7, wherein a material for the anode layer comprises indium tin oxide, fluorine-doped tin oxide, gold or graphene.

9. The white organic light emitting diode of claim 7, wherein a material for the hole injection layer comprises polyethylenedioxythiophene-poly(styrenesulfonate), N,N′-dipheny-N,N′-(1-naphthyl)-1′1-biphenyl-4,4′-diamine, tirs(4-carbazole-yl-phenyl)amine, or molybdenum trioxide.

10. The white organic light emitting diode of claim 7, wherein a material for the electron transport layer comprises 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene, bathophenanthroline or 1,3-bis(3,5-di(pyridin-3-yl)phenyl)benzene.

11. The white organic light emitting diode of claim 7, wherein a material for the electron injection layer comprises lithium fluoride, cesium fluoride, or 8-hydroxyquinolinolato lithium.

12. The white organic light emitting diode of claim 7, wherein a material for the cathode layer comprises aluminum, silver, magnesium silver alloy, or calcium; optionally, a mass ratio of magnesium to silver in the magnesium silver alloy is 1:(8 to 12).

13. The white organic light emitting diode of claim 7, wherein, the substrate comprises a glass film, a quartz film, a polyimide film, a polyethylene terephthalate film, or a metal film.

14. The white organic light emitting diode of claim 7, wherein the anode layer has a thickness of 100 nm to 300 nm; optionally, the hole injection layer has a thickness of 10 nm to 30 nm; optionally, the white light emitting layer has a thickness of 20 nm to 60 nm; optionally, the electron transport layer has a thickness of 20 nm to 60 nm; optionally, the electron injection layer has a thickness of 0.2 nm to 0.8 nm; optionally, the cathode layer has a thickness of 80 nm to 200 nm.

15. A preparation method of the white organic light emitting diode of claim 7, comprising: taking a substrate material with an anode layer, and sequentially preparing and forming a hole injection layer, a white light emitting layer, an electron transport layer, an electron injection layer and a cathode layer on the anode layer sequentially, to obtain the white organic light emitting diode.

16. The preparation method of the white organic light emitting diode of claim 15, wherein a manner of preparation and formation comprises any one or a combination of at least two of thermal evaporation, spin coating, brush coating, spray coating, roll coating, printing or ink jet printing.

17. The preparation method of the white organic light emitting diode of claim 16, wherein the preparation method comprises the following steps: (1) taking a substrate material with an anode layer, and spin-coating a hole injection layer material on a surface of the anode layer to form a hole injection layer; (2) heating the product obtained in the step (1); (3) depositing a white light emitting material on the hole injection layer of the product obtained in the step (2) via thermal vacuum evaporation to form a white light emitting layer; (4) heating the product obtained in the step (3), and cooling the product; and (5) depositing an electron transport layer, an electron injection layer and a cathode layer on the white light emitting layer of the product obtained in the step (4) sequentially, to obtain the white organic light emitting diode.

18. The preparation method of the white organic light emitting diode of claim 17, further comprising: ultrasonically washing the substrate material with an anode layer in purified water, acetone and isopropanol sequentially for 5 min to 20 min respectively, before the hole injection layer material is spin-coated on the surface of the anode layer material in the step (1).

19. The preparation method of the white organic light emitting diode of claim 17, wherein the heating in the step (2) refers to heating the product obtained in the step (1) to a temperature between 130° C. and 170° C. and keeping at this temperature for 10 min to 20 min; optionally, the thermal vacuum evaporation in the step (3) is carried out under an atmospheric pressure of 10.sup.−5 to 10.sup.−4 Pa; optionally, a rate of the thermal vacuum evaporation in the step (3) is 0.1 Å/sec to 0.5 Å/sec; optionally, the heating in the step (4) refers to heating to a temperature between 120° C. and 230° C. within 10 s and keeping at this temperature for 10 s to 1 min; optionally, the cooling in the step (4) refers to cooling to a temperature between 20° C. and 30° C. within 3 min.

20. The preparation method of the white organic light emitting diode of claim 17, wherein the preparation method comprises the following steps: (1) ultrasonically washing a substrate material with an anode layer in purified water, acetone and isopropanol sequentially for 5 min to 20 min respectively; (2) spin-coating a hole injection layer material on a surface of the anode layer cleaned in the step (1) to form a hole injection layer; (3) heating the product obtained in the step (2) to a temperature between 130° C. and 170° C., and keeping at this temperature for 10 min to 20 min; (4) depositing a white light emitting material on the hole injection layer of the product obtained in the step (3) via thermal vacuum evaporation at a rate of 0.1 Å/sec to 0.5 Å/sec under an atmospheric pressure of 10.sup.−5 Pa to 10.sup.−4 Pa to form a white light emitting layer; (5) heating the product obtained in the step (4) to a temperature between 120° C. and 230° C. within 10 s, then keeping at this temperature for 10 s to 1 min, and cooling to a temperature between 20° C. and 30° C. within 3 min; and (6) depositing an electron transport layer, an electron injection layer and a cathode layer on the white light emitting layer of the product obtained in the step (5) sequentially, to obtain the white organic light emitting diode.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a .sup.1hydrogen-nuclear magnetic resonance (.sup.1H-NMR) characteristic diagram of a compound in Example 1;

(2) FIG. 2 is a .sup.1H-NMR characteristic diagram of the compound in Example 1;

(3) FIG. 3 is a .sup.1H-NMR characteristic diagram of a compound in Example 2;

(4) FIG. 4 is a .sup.1H-NMR characteristic diagram of the compound in the example 2;

(5) FIG. 5 is a luminance-current density-voltage curve graph of a white organic light emitting diode;

(6) FIG. 6 is an emission spectrum-current density curve graph of a white organic light emitting diode; and

(7) FIG. 7 is a color coordinate diagram of a white organic light emitting diode.

DETAILED DESCRIPTION

(8) The technical solutions of the present disclosure are further described below through specific examples. Those skilled in the art should understand that the examples described herein are merely used for a better understanding of the present disclosure and should not be construed as specific limitations to the present disclosure.

Example 1

(9) A white light emitting material having a chemical structural formula represented by the following formula is synthesized in this example.

(10) ##STR00002##
The preparation method includes steps described below.

(11) (1) 5.0 mmol of tris(4-iodophenyl)amine, 21.0 mmol of 4-methoxyphenylacetylene, 30.0 mL of tetrahydrofuran and 7.0 mL of trimethylamine were loaded into a 100 mL two-necked flask equipped with a stir bar and connected to a reflux tube.

(12) (2) The reaction mixture was vacuumized by using a vacuum pump. The pressure reached 1×10.sup.−2 Pa before nitrogen was introduced. Vacuuming and refilling nitrogen were repeatedly carried out for three times, and the reaction system was kept under an atmosphere of nitrogen.

(13) (3) 0.125 mmol of tetrakis(triphenylphosphine)palladium and 0.8 mmol of cuprous iodide were added into the reaction solution under an atmosphere of nitrogen.

(14) (4) The reaction mixture was heated to 70° C. under the protection of nitrogen and kept refluxing for 10 hours. The solvent was then evaporated by using a rotary evaporator, and the residue was washed with a small amount of ethyl acetate to give yellow powder, which was purified by column chromatography (silica column: Yantai Jiangyou F-254 200-300 mesh, mobile phase: a mixed solvent of dichloromethane and n-hexane in a volume ratio of 1:30) to obtain white solid powder, i.e., the white light emitting material.

(15) The obtained white solid powder was characterized by C nuclear magnetic resonance (.sup.13C NMR) and .sup.1H NMR. The .sup.1H NMR data is shown in FIG. 1, and specifically is: .sup.1H NMR (Bruker 600 MHz, CDCl.sub.3) δ 7.45 (doublet, J=7.1 Hz, 6H), 7.43-7.38 (multiplet, 6H), 7.09-7.02 (multiplet, 6H), 6.91-6.85 (multiplet, 6H), 3.83 (singlet, 9H).

(16) The .sup.13C NMR data is shown in FIG. 2, and specifically is: .sup.13C NMR (Bruker 151 MHz, CDCl.sub.3) chemical shift δ 159.73, 146.68, 133.16, 132.80, 124.19, 118.41, 115.73, 114.21, 89.41, 88.13, 55.51.

(17) The data proves that this compound was successfully synthesized.

Example 2

(18) A white light emitting material having a chemical structural formula represented by the following formula is synthesized in this example.

(19) ##STR00003##

(20) The preparation method includes steps described below.

(21) (1) 5.0 mmol of tris(4-iodophenyl)amine, 21.0 mmol of methyl 4-ethynylbenzoate, 30.0 mL of tetrahydrofuran and 7.0 mL of trimethylamine were loaded into a 100 mL two-necked flask equipped with a stir bar and connected to a reflux tube.

(22) (2) The reaction mixture was vacuumed by a vacuum pump. The pressure reached 1×10.sup.−2 Pa before nitrogen was introduced. Vacuuming and refilling nitrogen were repeatedly carried out for three times, and the reaction system was kept under an atmosphere of nitrogen.

(23) (3) 0.125 mmol of tetrakis(triphenylphosphine)palladium and 0.8 mmol of cuprous iodide were added into the reaction solution under an atmosphere of nitrogen.

(24) (4) The reaction mixture was heated to 70° C. under the protection of nitrogen and kept refluxing for 10 hours. The solvent was then evaporated by using a rotary evaporator, and the residue was washed with a small amount of ethyl acetate to give yellow powder, which was purified by column chromatography (silica column: Yantai Jiangyou F-254 200-300 mesh, mobile phase: a mixed solvent of dichloromethane and n-hexane in a volume ratio of 1:30) to obtain white solid powder, i.e., the white light emitting material.

(25) The obtained white solid powder was characterized by .sup.1H NMR and .sup.13C NMR. The .sup.1H NMR data is shown in FIG. 3, and specifically is: .sup.1H NMR (Bruker 600 MHz, CDCl.sub.3) chemical shift δ 8.02 (doublet, J=8.3 Hz, 6H), 7.57 (doublet, J=8.4 Hz, 6H), 7.46 (doublet, J=8.6 Hz, 6H), 7.10 (doublet, J=8.7 Hz, 6H), 3.93 (singlet, 9H).

(26) The .sup.13C NMR data is shown in FIG. 4, and specifically is: .sup.13C NMR (Bruker 151 MHz, CDCl.sub.3) chemical shift δ 166.57, 146.96, 133.05, 131.40, 129.55, 129.36, 128.09, 124.11, 117.58, 92.26, 88.77, 52.24.

(27) The data proves that this compound was successfully synthesized.

Example 3

(28) A white organic light emitting diode is provided in this example. The preparation method of the white organic light emitting diode includes steps described below.

(29) (1) A glass substrate with 200 nm ITO as the anode material was ultrasonically washed for 15 min in purified water, acetone and isopropanol sequentially.

(30) (2) 20 nm-thick polyethylenedioxythiophene-poly(styrenesulfonate) was spin-coated on the surface of the ITO material cleaned in the step (1).

(31) (3) The product obtained in the step (2) was placed on a heating table, and heated to 150° C., and then kept at this temperature for 15 min.

(32) (4) The material prepared in the example 1 was deposited on the polyethylenedioxythiophene-poly(styrenesulfonate) layer of the product obtained in the step (3) via thermal vacuum evaporation at a rate of 0.5 Å/sec at an atmospheric pressure of 10.sup.−5 Pa to form a 40 nm white light emitting layer.

(33) (5) The product obtained in the step (4) was heated to 150° C. within 10 s, kept for 20 s, and then cooled to 25° C. within 3 min.

(34) (6) A 40 nm TPBi layer, a 0.5 nm lithium fluoride layer and a 130 nm aluminum layer were sequentially deposited on the white light emitting layer of the product obtained in the step (5) to obtain the white organic light emitting diode.

Example 4

(35) A white organic light emitting diode is provided in this example. The preparation method of the white organic light emitting diode includes steps described below.

(36) (1) A glass substrate with 100 nm ITO as the anode material was ultrasonically washed for 20 min in purified water, acetone and isopropanol sequentially.

(37) (2) 30 nm-thick polyethylenedioxythiophene-poly(styrenesulfonate) was spin-coated on the surface of the ITO material cleaned in the step (1).

(38) (3) The product obtained in the step (2) was placed on a heating table, and heated to 130° C., and then kept at this temperature for 20 min.

(39) (4) The material prepared in Example 2 was deposited on the polyethylenedioxythiophene-poly(styrenesulfonate) layer of the product obtained in the step (3) via thermal vacuum evaporation at a rate of 0.3 Å/sec at an atmospheric pressure of 10.sup.−5 Pa to form a 60 nm white light emitting layer.

(40) (5) The product obtained in the step (4) was heated to 200° C. within 10 s, kept for 10 s, and then cooled to 25° C. within 3 min.

(41) (6) A 20 nm TPBi layer, a 0.8 nm lithium fluoride layer and an 80 nm aluminum layer were sequentially deposited on the white light emitting layer of the product obtained in the step (5) to obtain the white organic light emitting diode.

Example 5

(42) A white organic light emitting diode is provided in this example. The preparation method of the white organic light emitting diode includes steps described below.

(43) (1) A glass substrate with 300 nm ITO as the anode material was ultrasonically washed for 15 min in purified water, acetone and isopropanol sequentially.

(44) (2) 10 nm-thick polyethylenedioxythiophene-poly(styrenesulfonate) was spin-coated on the surface of the ITO material cleaned in the step (1).

(45) (3) The product obtained in the step (2) was placed on a heating table, and heated to 170° C., and then kept at this temperature for 10 min.

(46) (4) The material prepared in Example 1 was deposited on the polyethylenedioxythiophene-poly(styrenesulfonate) layer of the product obtained in the step (3) via thermal vacuum evaporation at a rate of 0.5 Å/sec at an atmospheric pressure of 10.sup.−4 Pa to form a 20 nm white light emitting layer.

(47) (5) The product obtained in the step (4) was heated to 170° C. within 10 s, kept for 30 s, and then cooled to 25° C. within 3 min.

(48) (6) A 60 nm TPBi layer, a 0.2 nm lithium fluoride layer and a 200 nm aluminum layer were sequentially deposited on the white light emitting layer of the product obtained in the step (5) to obtain the white organic light emitting diode.

Example 6

(49) A white organic light emitting diode is provided in this example. The preparation method of the white organic light emitting diode includes steps described below.

(50) (1) A glass substrate with 200 nm graphene as the anode material was ultrasonically washed for 15 min in purified water, acetone and isopropanol sequenctially.

(51) (2) 20 nm-thick molybdenum trioxide was spin-coated on the surface of the graphene material cleaned in the step (1).

(52) (3) The product obtained in the step (2) was placed on a heating table, and heated to 150° C., and then kept at this temperature for 15 min.

(53) (4) The material prepared in Example 1 was deposited on the molybdenum trioxide layer of the product obtained in the step (3) via thermal vacuum evaporation at a rate of 0.5 Å/sec at an atmospheric pressure of 10.sup.−5 Pa to form a 40 nm white light emitting layer.

(54) (5) The product obtained in the step (4) was heated to 120° C. within 10 s, kept for 1 min, and then cooled to 20° C. within 3 min.

(55) (6) A 40 nm bathophenanthroline layer, a 0.5 nm cesium fluoride layer and a 130 nm magnesium silver alloy layer were sequentially deposited on the white light emitting layer of the product obtained in the step (5) to obtain the white organic light emitting diode.

Example 7

(56) A white organic light emitting diode is provided in this example. The preparation method of the white organic light emitting diode includes steps described below.

(57) (1) A glass substrate with 200 nm gold as the anode material was ultrasonically washed for 15 min in purified water, acetone and isopropanol sequentially.

(58) (2) 20 nm-thick TCTA was spin-coated on the surface of the gold material cleaned in the step (1).

(59) (3) The product obtained in the step (2) was placed on a heating table, and heated to 150° C., and then kept at this temperature for 15 min.

(60) (4) The material prepared in Example 2 was deposited on the TCTA layer of the product obtained in the step (3) via thermal vacuum evaporation at a rate of 0.5 Å/sec at an atmospheric pressure of 10.sup.−5 Pa to form a 40 nm white light emitting layer.

(61) (5) The product obtained in the step (4) was heated to 230° C. within 10 s, kept for 10 s, and then cooled to 30° C. within 3 min.

(62) (6) A 40 nm B3PyPB layer, a 0.5 nm 8-hydroxyquinolinolato lithium layer and a 130 nm sliver layer were sequentially deposited on the white light emitting layer of the product obtained in the step (5) to obtain the white organic light emitting diode.

Example 8

(63) Evaluation:

(64) The performance of the white organic light emitting diodes prepared in the example 3 and example 4 were evaluated as follows.

(65) (1) Luminance-current density-voltage curve test: A Keithley Model 2634 type source meter was connected to the anode end and the cathode end of the organic light emitting diode. The voltage between the anode and the cathode was adjusted for scanning, where the scanning area was 0 V to 15 V, and the current value and the voltage value were recorded. The corresponding luminance value was read out by a PR670 luminance meter, and a luminance-current density-voltage curve was drawn.

(66) The test results are shown in FIG. 5 (the arrow in the figure indicates that the vertical coordinate of the circled curves is the luminance on the right-hand side). It can be seen from the graph that: the turn-on voltage of the light emitting diode is about 6 V, and the maximum luminance is about 2000 cd/m.sup.2.

(67) (2) Emission spectrum-current density curve test: A Keithley Model 2634 type source meter was connected to the anode end and the cathode end of the organic light emitting diode. The mode was adjusted to be a current source mode, and the current density value was adjusted to be from 1 mA/cm.sub.2 to 50 mA/cm.sub.2. The spectrum of the light emitting diode was tested by using an ocean spectrometer 2000.

(68) The test results are shown in FIG. 6, and it can be seen from the graph that the peak value of the light emitting spectrum has no large shift under different current densities, suggesting that the light emitting diode has excellent color stability.

(69) (3) Color coordinate test: A Keithley Model 2634 source meter was connected to the anode end and the cathode end of the organic light emitting diode. The mode was adjusted to be a current source mode, and the current density value was adjusted to be 10 mA/cm.sub.2. The spectrum of the light emitting diode was tested by using an ocean spectrometer 2000, and the color coordinate was measured by using spectrasite software.

(70) The test results are shown in FIG. 7, and it can be seen from the graph that, when the substituent —R is —OCH.sub.3, the color coordinates of the light emitting diode are (0.2938, 0.3104), and when the substituent —R is —COOCH.sub.3, the color coordinates of the light emitting diode are (0.3483, 0.3509).

(71) The applicant has stated that although the white light emitting material, a preparation method thereof, and application thereof in the present disclosure are described through the examples described above, the present disclosure is not limited to the examples described above, which means that implementation of the present disclosure does not necessarily depend on the examples described above. It should be apparent to those skilled in the art that any improvements made to the present disclosure, equivalent replacements of various raw materials of the product, the addition of adjuvant ingredients, and the selection of specific manners, etc. in the present disclosure all fall within the protection scope and the scope of disclosure of the present disclosure.

(72) Though the preferred embodiments of the present disclosure have been described above in detail, the present disclosure is not limited to the above-described embodiments, and various simple modifications can be made to the technical solutions of the present disclosure without departing from the scope of the present disclosure. These simple modifications are all within the scope of the present disclosure.

(73) In addition, it is to be noted that if not in collision, the specific technical features described in the above specific embodiments may be combined in any suitable manner. In order to avoid unnecessary repetition, the present disclosure does not further specify any of various possible combination manners.